function nav_set(obj,tag_N){
		var nav_list= document.getElementById("nav_list").getElementsByTagName("li");
		var nav_cont=document.getElementById("nav_cont").getElementsByTagName("h1");
		for(var i=0;i<nav_list.length;i++){
			nav_list[i].className="";	
			nav_cont[i].className="cont_tag";
			}
		obj.className="slelcted";
		document.getElementById(tag_N).className="cont_tag_show";
		
		}
function nav_set_kuaijie(obj,tag_N){
		var nav_list= document.getElementById("nav_list").getElementsByTagName("A");
		var nav_cont=document.getElementById("nav_cont").getElementsByTagName("h1");
		for(var i=0;i<nav_list.length;i++){
			nav_list[i].className="";	
			nav_cont[i].className="cont_tag";
			}
			obj.className="hover";
		document.getElementById(tag_N).className="cont_tag_show";
		
		}



function slelct_box(obj,obj_this){		
	var shang=document.getElementById("shang");
	var xia=document.getElementById("xia");
	var zhongline=document.getElementById("zhongline");
	var toparrow=document.getElementById("toparrow");
	var obj=document.getElementById(obj);	
	if(obj.style.display=="none"){
		obj.style.display="block";
	
		}
	else {
		obj.style.display="none";		
		
		}
	if(		obj_this.className=="downarrow")
		{
		
			obj_this.className="toparrow";
			
		}
		
	else{		
			obj_this.className="downarrow";
		}

	}
function slelct_box_xia(obj,obj_this){		
	var shang=document.getElementById("shang");
	var xia=document.getElementById("xia");
	var zhongline=document.getElementById("zhongline");
	var toparrow=document.getElementById("toparrow");
	var obj=document.getElementById(obj);	
	if(obj.style.display=="none"){
		obj.style.display="block";
	
		}
	else {
		obj.style.display="none";		
		
		}
	if(	obj_this.className=="downarrow")
		{
		
			obj_this.className="toparrow";
			zhongline.className="topposi";

			
			
		}
		
	else{		
			obj_this.className="downarrow";
			zhongline.className="";
			
			
		}

	}